Verizon Wireless is the best performing network, followed by AT&T, Sprint, and T-Mobile. Analytics firm RootMetrics recently released those rankings, which pleased Verizon and obviously upset T-Mobile.

RootMetrics measure the reliability, speed, and performance for data, calls, or texting of all four major networks. The company traveled nearly 218,000 miles to test performance in 6,300 indoor locations across the United States. In all tests but the speed index, which rated AT&T top at 88.7 and Verizon second at 88.5, Verizon Wireless was the leader. T-Mobile snagged third place in the speed test at 74.3, ahead of Sprint's 65.8, but it ranked last in all other categories.

T-Mobile was predictably not pleased with the rankings. CTO Neville Ray called the entire premise into question because the tests were conducted in the later half of 2013. He added that T-Mobile is the "clear leader and has been for several months" when it comes to crowdsourced tests from Ookla's Speedtest.net.

Ray's argument is questionable. T-Mobile's 4G LTE network launched in July 2013, around the time that RootMetrics says it started recording tests. It's important to note that several more cities did not get LTE until later in the year, so it's possible that RootMetrics tested in some places prior to launching, but T-Mobile spent much of 2012 arguing that it's HSPA+ was just as good as fast as the LTE networks of its rivals, so why complain about that distinction now?

The Speedtest argument is even weaker because those tests include less statistical control and only measure speed; RootMetrics tests also looked at other areas of network performance for calls and reliability. While it's great to flex the strong speeds in downtown cores and places where T-Mobile is ahead of the competition in major markets, T-Mobile's coverage gaps are greater in suburban and rural areas, something even Ray acknowledged.

"When we move out into rural areas where we don't serve, obviously we don't have a competitive experience. But we are working on that. We will be working on that more with what we do with our [700 MHz] A Block deployment. And we look to level the playing field across a broader swath of geography across the coming years."

T-Mobile CEO John Legere also responded by calling Root Metrics methods "slanted" and "old news" because T-Mobile moves so quickly. However, Root Metrics once factored into T-Mobile's very own coverage maps and was even promoted by the company in 2012. You can learn more about RootMetrics and its results by visiting the company's website.